US7662297B2 - Method of and apparatus for separation of scum from a liquid - Google Patents

Method of and apparatus for separation of scum from a liquid Download PDF

Info

Publication number
US7662297B2
US7662297B2 US11/632,430 US63243005A US7662297B2 US 7662297 B2 US7662297 B2 US 7662297B2 US 63243005 A US63243005 A US 63243005A US 7662297 B2 US7662297 B2 US 7662297B2
Authority
US
United States
Prior art keywords
paddles
scum
wall
housing
water
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related, expires
Application number
US11/632,430
Other languages
English (en)
Other versions
US20080296235A1 (en
Inventor
Bradley Desmond Leslie Murray
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
PACE SOLUTIONS Pty Ltd
Original Assignee
PACE SOLUTIONS Pty Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from AU2004903828A external-priority patent/AU2004903828A0/en
Application filed by PACE SOLUTIONS Pty Ltd filed Critical PACE SOLUTIONS Pty Ltd
Publication of US20080296235A1 publication Critical patent/US20080296235A1/en
Assigned to PACE SOLUTIONS PTY LTD. reassignment PACE SOLUTIONS PTY LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: MURRAY, BRADLEY DESMOND LESLIE
Application granted granted Critical
Publication of US7662297B2 publication Critical patent/US7662297B2/en
Expired - Fee Related legal-status Critical Current
Adjusted expiration legal-status Critical

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/24—Treatment of water, waste water, or sewage by flotation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/24—Feed or discharge mechanisms for settling tanks
    • B01D21/2433—Discharge mechanisms for floating particles
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00—Biological treatment of water, waste water, or sewage
    • C02F3/02—Aerobic processes
    • C02F3/12—Activated sludge processes
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2303/00—Specific treatment goals
    • C02F2303/12—Prevention of foaming
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W10/00—Technologies for wastewater treatment
    • Y02W10/10—Biological treatment of water, waste water, or sewage

Definitions

  • THIS INVENTION relates to a method of and apparatus for the separation of scum from a liquid.
  • the invention has particular application to separation of scum created by aerobic digestion of waste water.
  • the invention may also have application to the separation of the foam or froth phase formed by dispersed or dissolved air flotation used in, for example, waste water treatment. It will be appreciated that the invention is not limited to treatment of waste water. It will also be appreciated that the invention is applicable to liquids other than water.
  • sludge is sometimes used in the art to refer to the scum floating on the surface of the liquid, and sometimes to the thickened or dewatered scum. Other terms, such as spume or head may be used, but in this specification, the term “sludge” refers to the thickened scum formed as a result of dewatering the scum unless the context requires otherwise.
  • British Patent No. 2,193,113 discloses a harvester for harvesting floating matter, such as floating weeds or scum from water by a series of paddles mounted between two substantially parallel running endless chains.
  • the harvester disclosed has relatively complex mechanical elements immersed in water which results in relatively high maintenance costs.
  • the present invention aims to provide a method of and apparatus for the separation of scum from a liquid which alleviates one or more of the disadvantages of the prior art.
  • Other aims and advantages of the invention may become apparent from the following description.
  • this invention in one aspect resides broadly in apparatus for the separation of scum from a liquid including:
  • the rotational locus is selected to provide an increase in depth of the water as it is in use being lifted.
  • the invention resides broadly in apparatus for the separation of scum from a liquid including:
  • the substantial sealing engagement is selected to provide at least partial dewatering of the scum and water being lifted by the or each paddle between the opposed inner faces of the side walls by the rotation of the paddles in use.
  • the rotational device is constituted by a rotor and the scraper wall is constituted by an arcuate curved wall arranged in circumferential disposition with respect to the axis of the rotor.
  • the arc of the curved wall terminates at a position which enables the dewatered scum to be ejected from the space above the paddle by natural gravitational fall.
  • the outward periphery of the some of the paddles is provided with combs or a plurality of fingers extending substantially radially, but being either resiliently flexible or terminating short of the curved wall, and the remainder of the paddles are provided with a flexible sheet extending to engage with the curved face of the curved wall.
  • at least one face of the flexible sheet is contoured to provide the selected drainage.
  • the extent of the teeth or tines of the comb or the fingers are such that they may be deflected by their engagement with the curved wall to collectively provide the selected sealing engagement. Accordingly, in a preferred form, some of the paddles are provided with a higher degree of sealing than others. Preferably, two or three paddles are provided with the comb-like extremities, followed by a paddle having the contoured flexible sheeting having a more limited leakage.
  • the rotational device may be constituted by a belt having the paddles extending outwardly and the belt being rotatable about two or more rollers.
  • the scraper wall is shaped to provide the spaced disposition with respect to the locus of the paddles along the path of the belt around the rollers.
  • the present invention resides broadly in a method of separating scum from a liquid including:
  • the fixed and moving walls of the separating apparatus form respective parts of the housing and paddle or paddles as hereinbefore described.
  • the present invention resides broadly in a method of separating scum from a liquid including:
  • the scum is de-aerated by being fed through chambers having pulsating pressure variations.
  • the method may include feeding the scum through a diaphragm pump or the like.
  • FIG. 1 is a diagrammatic side view of a paddle assembly for separation apparatus according to the invention
  • FIG. 2 is a diagrammatic side view of the apparatus of FIG. 1 with the paddle assembly in a different orientation;
  • FIG. 3 is a diagrammatic side view of the apparatus of FIGS. 1 and 2 the paddle assembly in an orientation different from that of FIGS. 1 and 2 ;
  • FIG. 4 is a diagrammatic side view of the apparatus incorporating the paddle assembly of FIGS. 1 to 3 , but showing the arrangement of the housing;
  • FIG. 5 is a diagrammatic pictorial view of part of the apparatus of FIGS. 1 to 4
  • FIG. 6 is a pictorial view generally of separation apparatus according to the invention.
  • FIG. 7 is a pictorial view of the paddle assembly shown in FIGS. 1 to 4 for the separation apparatus of FIG. 6 .
  • the rotor 12 for separation apparatus 10 shown in FIGS. 1 to 7 includes plurality of paddles, four of which are shown with reference numerals 13 , 14 , 15 and 16 in FIGS. 1 to 3 .
  • the paddles are arranged at an angle skewed to radial with a circumferential component such that the inner edges of the paddle precede the outer peripheral edges in the direction of rotation shown by arrow 34 .
  • the faces of the paddles have a substantially constant circumferential component in the axial direction and are substantially planar.
  • the rotor is rotated in the direction shown in order to engage with a curved wall 20 in order to capture scum between the leading face of each paddle and the trailing face of the paddle in front of it.
  • the rotor is shown with four of the paddles in a previous position of rotation respectively and as indicated by a reference arrow 32 .
  • the four paddles form a set in which those marked “R” (that is, those having reference numerals 14 , 15 and 16 ) are “rake” type paddles having fixed fingers or tines akin to a rake along the outward peripheries, and that marked “S” (that is, the paddle with reference numeral 13 ) is a “scraper” type paddle having a contoured flexible sheet along its outward periphery.
  • the scum 17 is picked up from atop the liquid 18 and by virtue of the change in geometric shape of the body of liquid retained between the paddles during rotation, the scum becomes thicker, the depth of the volume defined by the paddle and the curved wall becoming greater as the paddle is moved along the curved wall.
  • a scum collection chamber 25 shown in FIGS. 1 to 4 forms part of a housing 22 (not shown in FIGS. 1 to 4 ) in which the rotor is mounted.
  • the paddles are mounted between two parallel circular side plates. It can be seen that there is a gap between the periphery of the circular side plates of the rotor between which the paddles are mounted and the curved wall of the housing, the paddles extending past the periphery of the side plates of the rotor such that only a portion of the peripheral extremity of the rotor is required to seal against the curved wall and part of the sides of the housing.
  • a forward lip 24 is preferably provided at approximately 45° downwards from the leading edge of the curved wall to engage with the flexible fingers attached to the peripheral edges of each paddle.
  • scum is guided up the wall in the direction of arrows 35 whilst water is permitted to drain therefrom and run down the curved wall as represented by arrows 36 .
  • the drained water continues along with the remainder of the water as indicated by arrows 37 , and the scum is discharged over the upper edge of the curved wall as represented by the arrow 38 .
  • the separation apparatus is enclosed within the housing 22 up to about the axle level of the rotor, and the upper portion of the rotor is enclosed in a cover 23 extending also over the top of the scum collection chamber.
  • the cover is in two parts: an upper cover 26 and a lower cover 27 , the upper cover being detachable from the lower cover to provide access to the rotor.
  • scum can collect on the side walls.
  • provision of a spray system spraying water from beneath the scum against the side walls has surprisingly been found to detach the scum from the side walls and allow the scum to train into a slick with side edges spaced from the side walls of the feed channel.
  • this permits better flow of scum with the water underneath to afford the separation apparatus of the present invention the opportunity to pick the scum off the surface of the water, draining most of the water (and possibly some of the scum) back to the feed stream with a dynamic equilibrium being substantially established as the rotor rotates such entry of the scum into the rotor is streamlined. It is believed such an arrangement advantageously permits better efficacy to provide a relatively dewatered scum from the scum collection chamber.
  • the spray may be provided by a perforated pipe running axially along the channel above the liquid level, the perforations being spaced to enable the liquid to spread out across the face of the sides of the channel when it strikes thereagainst.
  • the spray is provided by having two pipes, tube or hoses having a flange extending radially downward and having perforations along the tube in proximity to the proximal edge of the flange, permitting the liquid to be guided down the flange. In use the tubes are mounted such that the flanges engage with the side faces of the channel to wet same and perform the scum removal action.
  • discharging scum from the scum collection chamber is advantageously performed using a diaphragm pump.
  • the pulsatory action or some other mechanism has been found to de-aerate the scum to a more concentrated form, that is, having less air.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Biodiversity & Conservation Biology (AREA)
  • Microbiology (AREA)
  • Removal Of Floating Material (AREA)
US11/632,430 2004-07-13 2005-07-13 Method of and apparatus for separation of scum from a liquid Expired - Fee Related US7662297B2 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
AU2004903828A AU2004903828A0 (en) 2004-07-13 Method of and Apparatus for Separation of Scum from a Liquid
AU2004903828 2004-07-13
PCT/AU2005/001026 WO2006005132A1 (en) 2004-07-13 2005-07-13 Method of and apparatus for separation of scum from a liquid

Publications (2)

Publication Number Publication Date
US20080296235A1 US20080296235A1 (en) 2008-12-04
US7662297B2 true US7662297B2 (en) 2010-02-16

Family

ID=35783454

Family Applications (1)

Application Number Title Priority Date Filing Date
US11/632,430 Expired - Fee Related US7662297B2 (en) 2004-07-13 2005-07-13 Method of and apparatus for separation of scum from a liquid

Country Status (7)

Country Link
US (1) US7662297B2 (zh)
EP (1) EP1784361A4 (zh)
JP (1) JP2008505755A (zh)
CN (1) CN100564268C (zh)
CA (1) CA2614515C (zh)
NZ (1) NZ553121A (zh)
WO (1) WO2006005132A1 (zh)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FI123404B (fi) * 2008-08-04 2013-03-28 Insinoeoeritoimisto Oy Ricson Ab Lietteenpoistolaitteisto
EP2290192A1 (en) 2009-08-19 2011-03-02 Services Pétroliers Schlumberger Apparatus and method for autofill equipment activation
CN104528860A (zh) * 2015-01-13 2015-04-22 王林 带浮渣脱水功能的气浮机
PL3093567T3 (pl) * 2015-05-12 2018-01-31 Venta Luftwaescher Gmbh Zasobnik filtra, walec i nawilżacz powietrza
GB201611364D0 (en) * 2016-06-30 2016-08-17 F M Enviromental Ltd A Containment recovery device
CN109516520B (zh) * 2018-12-28 2021-09-10 李奇元 环保污水处理用平流气浮池排渣装置
CN110904931B (zh) * 2019-11-19 2021-04-27 江苏科技大学 水面垃圾打捞装置
CN114308992A (zh) * 2021-11-26 2022-04-12 西安航天发动机有限公司 一种全封闭一体式智能餐厨垃圾处理箱及处理工艺
KR102411599B1 (ko) * 2022-02-18 2022-06-22 (주)동일캔바스엔지니어링 부력식 스컴 스키머

Citations (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1946663A (en) * 1930-11-05 1934-02-13 Simplicity Eng Co Dewatering device
US2267086A (en) * 1937-07-22 1941-12-23 William J Donohue Filtering method and apparatus
US2491912A (en) * 1947-01-30 1949-12-20 Marcus A Walker Apparatus for separating materials
US2822928A (en) 1954-12-24 1958-02-11 Infilco Inc Scum skimmer
US3447683A (en) * 1967-05-15 1969-06-03 Laval Turbine Separation apparatus and method for mixed impurities on the exposed surface of a liquid body
US3613891A (en) * 1970-03-24 1971-10-19 Anti Pollution Inc Oil removal apparatus
US3891558A (en) * 1972-12-06 1975-06-24 Jr Paul Condit Oil and debris removal unit
US4151081A (en) * 1971-06-04 1979-04-24 Seaclean Sa Process and plant for hydromechanical recovery of a fluid spread in a thin layer on the surface of another liquid
US4184967A (en) * 1978-06-22 1980-01-22 Lenox Institute For Research, Inc. Apparatus for clarifying waste water
SU823301A1 (ru) 1979-07-04 1981-04-23 Государственный Проектный Институтстроительного Машиностроения Устройство дл флотационной очистки воды
SU1404118A1 (ru) 1986-04-30 1988-06-23 Кузнецкий научно-исследовательский и проектно-конструкторский институт углеобогащения Флотационна машина
US5091083A (en) 1990-09-04 1992-02-25 Meylor Donald M Flotation separation system
US5158679A (en) * 1990-08-23 1992-10-27 Brock J R Crude oil and water separator
US5968353A (en) * 1997-11-14 1999-10-19 Beloit Technologies, Inc. Clarifier with sludge dewatering
US6136191A (en) * 1998-10-05 2000-10-24 Gribble; Donald L. Elevating solids separator and drive connection therefor
US6328888B1 (en) * 2000-07-13 2001-12-11 Environment Recovery Equipment Inc. Skimmer
US6364123B1 (en) * 1998-03-16 2002-04-02 Degremont Device for recuperating floating materials in a sedimentation tank

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1967310A (en) * 1931-01-07 1934-07-24 Kent Robert Sayre Sugar solution clarifier apparatus
US3700108A (en) * 1971-02-04 1972-10-24 Frank A Richards Oil skimmer
US3762558A (en) * 1971-09-30 1973-10-02 J Anderson Anti-pollution barge and conveyer assembly
FR2189325B1 (zh) * 1972-06-20 1974-12-27 Degremont
JPS6119768Y2 (zh) * 1980-01-18 1986-06-14
DE3125065A1 (de) * 1981-06-26 1983-01-05 Eschweiler Bergwerks-Verein AG, 5120 Herzogenrath "vorrichtung zum austragen von groben schwimmfaehigenverunreinigungen"
DE3934874C2 (de) * 1989-10-19 1996-12-12 Bernhard Kessel Verfahren zum Entsorgen einer Abscheideanlage und Abscheideanlage
JPH03284395A (ja) * 1990-03-30 1991-12-16 Ebara Corp 液体表面浮遊物の除去装置
GB2266476B (en) * 1992-04-30 1995-06-21 Robert Herbert Doe Liquid and foam collection device
US5540844A (en) * 1995-07-21 1996-07-30 Meylor; Donald M. Dewatering system

Patent Citations (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1946663A (en) * 1930-11-05 1934-02-13 Simplicity Eng Co Dewatering device
US2267086A (en) * 1937-07-22 1941-12-23 William J Donohue Filtering method and apparatus
US2491912A (en) * 1947-01-30 1949-12-20 Marcus A Walker Apparatus for separating materials
US2822928A (en) 1954-12-24 1958-02-11 Infilco Inc Scum skimmer
US3447683A (en) * 1967-05-15 1969-06-03 Laval Turbine Separation apparatus and method for mixed impurities on the exposed surface of a liquid body
US3613891A (en) * 1970-03-24 1971-10-19 Anti Pollution Inc Oil removal apparatus
US4151081A (en) * 1971-06-04 1979-04-24 Seaclean Sa Process and plant for hydromechanical recovery of a fluid spread in a thin layer on the surface of another liquid
US3891558A (en) * 1972-12-06 1975-06-24 Jr Paul Condit Oil and debris removal unit
US4184967A (en) * 1978-06-22 1980-01-22 Lenox Institute For Research, Inc. Apparatus for clarifying waste water
SU823301A1 (ru) 1979-07-04 1981-04-23 Государственный Проектный Институтстроительного Машиностроения Устройство дл флотационной очистки воды
SU1404118A1 (ru) 1986-04-30 1988-06-23 Кузнецкий научно-исследовательский и проектно-конструкторский институт углеобогащения Флотационна машина
US5158679A (en) * 1990-08-23 1992-10-27 Brock J R Crude oil and water separator
US5091083A (en) 1990-09-04 1992-02-25 Meylor Donald M Flotation separation system
US5968353A (en) * 1997-11-14 1999-10-19 Beloit Technologies, Inc. Clarifier with sludge dewatering
US6364123B1 (en) * 1998-03-16 2002-04-02 Degremont Device for recuperating floating materials in a sedimentation tank
US6136191A (en) * 1998-10-05 2000-10-24 Gribble; Donald L. Elevating solids separator and drive connection therefor
US6328888B1 (en) * 2000-07-13 2001-12-11 Environment Recovery Equipment Inc. Skimmer

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
International Search Report mailed Aug. 11, 2005 by the Australian Patent Office in counterpart foreign application No. PCT/AU2005/001026 and the International Preliminary Report on Patentability issued on Jan. 16, 2007 by the World Intellectual Property Office in counterpart foreign application No. PCT/AU2005/001026.

Also Published As

Publication number Publication date
CA2614515A1 (en) 2006-01-19
EP1784361A4 (en) 2011-06-15
JP2008505755A (ja) 2008-02-28
US20080296235A1 (en) 2008-12-04
CA2614515C (en) 2014-02-25
NZ553121A (en) 2010-09-30
CN101023031A (zh) 2007-08-22
CN100564268C (zh) 2009-12-02
EP1784361A1 (en) 2007-05-16
WO2006005132A1 (en) 2006-01-19

Similar Documents

Publication Publication Date Title
US7662297B2 (en) Method of and apparatus for separation of scum from a liquid
CN101318714B (zh) 一种收获水华蓝藻的方法及装置
KR930011684B1 (ko) 슬러리형상의 슬러지를 농축 및 탈수하기 위한방법
US5185087A (en) Method of concentrating and deodorizing ruminant waste
US4062776A (en) Sludge concentrator and conditioner
KR101047166B1 (ko) 고농도 유기성 폐수처리를 위한 부상분리장치
AU2005262285B2 (en) Method of and apparatus for separation of scum from a liquid
JP5605490B1 (ja) 加圧浮上式スカム分離処理装置
KR101156021B1 (ko) 음식물 쓰레기의 음폐수 처리장치
KR20170003069U (ko) 스컴 제거를 위한 혐기성 소화조
CN210764703U (zh) 一种工业废水处理沉淀池
EP0665794B1 (en) Apparatus for collecting floating material from the surface of a liquid
JP2008272630A (ja) ベルト式濃縮機及びその運転方法
KR101609534B1 (ko) 조류 제거장치
CN218931754U (zh) 一种高效除杂的污水处理细格栅
JPS6344009A (ja) 浮遊物の収穫装置
JP2004216288A (ja) し渣洗浄・脱水装置
GB2031295A (en) A de-watering plant for removing water from sludges and similar substances
SU854421A1 (ru) Радиальный сгуститель дл очистки сточных вод
JPH0871550A (ja) 液面浮遊物の吹寄せ装置
KR200283103Y1 (ko) 산화부상 가압 전분제거장치
WO2000010398A1 (en) Gut cleaning method and device for removal of fat or other floating substances
JPS5942085Y2 (ja) 汚泥濃縮槽
WO2024050570A1 (en) Slurry treatment apparatus
JP2001334259A (ja) スカム分離方法及びその装置

Legal Events

Date Code Title Description
AS Assignment

Owner name: PACE SOLUTIONS PTY LTD., AUSTRALIA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:MURRAY, BRADLEY DESMOND LESLIE;REEL/FRAME:023763/0471

Effective date: 20091216

Owner name: PACE SOLUTIONS PTY LTD.,AUSTRALIA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:MURRAY, BRADLEY DESMOND LESLIE;REEL/FRAME:023763/0471

Effective date: 20091216

STCF Information on status: patent grant

Free format text: PATENTED CASE

CC Certificate of correction
FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: SMALL ENTITY

REMI Maintenance fee reminder mailed
FPAY Fee payment

Year of fee payment: 4

SULP Surcharge for late payment
FPAY Fee payment

Year of fee payment: 8

FEPP Fee payment procedure

Free format text: MAINTENANCE FEE REMINDER MAILED (ORIGINAL EVENT CODE: REM.); ENTITY STATUS OF PATENT OWNER: SMALL ENTITY

LAPS Lapse for failure to pay maintenance fees

Free format text: PATENT EXPIRED FOR FAILURE TO PAY MAINTENANCE FEES (ORIGINAL EVENT CODE: EXP.); ENTITY STATUS OF PATENT OWNER: SMALL ENTITY

STCH Information on status: patent discontinuation

Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362

FP Lapsed due to failure to pay maintenance fee

Effective date: 20220216